Thixoforming requires semi-solid slurries, which contain a high volume fraction of non-dendritic solid phase with special grain morphology. Volume fraction, geometry and connectivity of the solid alpha-phase has to be kept within narrow limits. The paper illustrates the development of a new aluminium based wrought alloy AIMgSi1 alloy, adapted with barium, characterised by a microstructure which exhibits a low sensitivity towards fluctuations in process parameters resulting in improved mechanical properties of the alloy. The rheological behaviour of the new alloy by means of backward extrusion experiments is described, and an overview of the static and dynamic strength properties is given that can be achieved when the alloy is processed by means of the New Rheocasting process.